[Effect of zataria multiflora boiss. essential oil on the growth of listeria monocytogenes in salted fish]

Essential oils and their components have antimicrobial effects. They use with spices as flavoring agents all over the world. They have been used safely since ancient times as herbal medicines. Zataria multiflora Boiss. is one of medicinal herbs in Iran and its antimicrobial effects on foodborne pathogens have to investigate in foodstuff. The aim of this study was to determine of the effect of Zataria multiflora Boiss. Essential oil on the growth of Listeria monocytogenes in salted [4%] silver carp. Effect of different concentrations of this Essential oil [0.0%, 0.045%, 0.135%, 0.405%, and 0.810%] on behavior of Listeria monocytogenes was determined by evaluation of the bacterial growth in salted fish fillets. The essential oil in used concentrations had significant inhibitory effect on the growth of Listeria monocytogenes in salted fish during the storage time. The higher concentration until 0.405%, the more significant inhibitory effects on the growth of Listeria monocytogenes [p<0.05] but 0.405% and 0.810% concentrations had no different significant inhibitory effects on the growth of Listeria monocytogenes [p>0.05]. Organoleptical survey showed that the concentrations of the essential oil used until 0.405% not only had no undesirable effect on flavoring but also it improve taste and flavor of salted fish. The result suggested that the Zataria multiflora Boiss. Essential oil can be considered as a natural preservative in salted fish

Detection of single dactylogyrus spp. in DMA extracted from infected gill tissue of fishes using polymerase chain reaction

Dactylogyrus spp. are monogenean worms found mostly as ectoparasites on the gills of several fish species, including carp and goldfish. These parasites are commonly detected by microscopic analysis of the gill lamellae, but this is time-consuming and technically difficult. In contrast to this conventional method, molecular techniques provide specific, sensitive and safe detection of parasites. In the present study, polymerase chain reaction [PCR] and subsequent DNA sequencing were used to detect Dactylogyrus spp. Specific common primers were designed to amplify the ITS-1 region of the rRNA gene of Dactylogyrus spp. Dactylogyrus worms were collected from 100 goldfishes and identified using a dissection microscope. Then, single worms were used for DNA extraction. To evaluate the PCR, a single parasite was added to a parasite-free gill, which then had its DNA extracted. Subsequently, the PCR products were purified and sequenced. Comparison of the nucleotide sequences of the PCR products with GenBank sequences showed that there was 100% homology with sequences from two Dactylogyrus spp., namely Dactylogyrus vastator and Dactylogyrus dulkeiti [registered under accession numbers AJ 564159 and AJ 564126, respectively]. The results obtained from sequence analyses were consistent with species identification by microscopy. Therefore, the results show that it is possible to develop a sensitive and precise PCR method for the detection of Dactylogyrus-mfected fish using DNA extracted from the whole gill

[Effect of Zataria multiflora Boiss. essential oil on the behavior of Vibrio parahaemolyticus in salted fish]

Thyme [Zataria multiflora Boiss.] is one of the Iranian traditional spices and it has antimicrobial effect on the pathogenic bacteria which are agents for some current food borne intoxications. The aim of this study was to evaluate the antimicrobial activity of Zataria multiflora Boiss. essential oil on V. parahaemolyticus in salted [8% Nacl in tissue] silver carp. Effect of different concentrations of this Essential oil [0.0%, 0.045%, 0.135%, 0.405%, 0.810%] on behavior of V. parahaemolyticus in two temperatures [15, 25 C] was determined by evaluation of the bacterial growth in salted fish fillets. The essential oil in used concentrations had significant inhibitory effect on the growth of V. parahaemolyticus in salted fish compare with control treatment during the storage time [p<0.05]. There was no significant difference between all treatments. The results showed that Zataria multiflora Boiss. Essential oil had inhibitory effect on V. parahaemolyticus, therefore it can be considered as a natural preservative in salted fish

evaluation of eucaliptus camaldolensis dehnh. Esscence application in control of fungal pollution of trout eggs

The use of medical plants is necessary as the antifungal agent substitute the malachite green for control of fungal pollution in salmonid hatcharies. The capability of Eucaliptus camaldolensis escence in control of fungal pollution about 50 kg trout eggs 4 years old Oncorhynchus mykiss brooders were evaluated in clinical and farm conditions, with using of 1,5,10,25,50 and 100 ppm dosages of this escence daily with 3 repetition until the eyed egg stage [about 18-20 days]. Besides, under the equal condition, the positive control group was treated with 1 ppm malachite green and the negative control group was assessed without any drugs. After culturing of fungal eggs, a pollution of Saprolegnia parasitica and Fusarium solani was obsereved. MIC result of Eucaliptus escence against Saprolegnia was 2.3 and against Fusarium was 8.2 ppm. Measuring the physical and chemical factors of water, no negative effect is recognized. The eucalyptus escence specially in the doses of 25, 50 and 100 ppm is significantly different from negative control group [p< 0.05] and created suitable inhibition aginst water fungi